Following is an interesting example that displays calendar of the current month on the console.

Java Code:
GregorianCalendar d = new GregorianCalendar();

int today = d.get(Calendar.DAY_OF_MONTH);
int month = d.get(Calendar.MONTH);

d.set(Calendar.DAY_OF_MONTH, 1);

int weekday = d.get(Calendar.DAY_OF_WEEK);

System.out.println("Sun Mon Tue Wed Thu Fri Sat");

for (int i = Calendar.SUNDAY; i < weekday; i++)
System.out.print(" ");

do
{
int day = d.get(Calendar.DAY_OF_MONTH);

if (day < 10) System.out.print(" ");
System.out.print(day);

if(day == today)
System.out.print("* ");
else
System.out.print(" ");

if (weekday == Calendar.SATURDAY)
System.out.println();

d.add(Calendar.DAY_OF_MONTH, 1);
weekday = d.get(Calendar.DAY_OF_WEEK);

}

while (d.get(Calendar.MONTH) == month);

if (weekday != Calendar.SUNDAY)
System.out.println();